Strongly correlated cage compounds for thermoelectric applications?

Both in the class of strongly correlated electron systems and in the class of cage compounds representatives with appealing thermoelectric properties exist. The former ones are characterized by large thermopower values, the latter ones show low and "glass-like" phonon thermal conductivities. The combination of both properties within a single compound, however, has proven challenging. We review some of our recent investigations on various cage compounds containing rare-earth elements as guest atoms and discuss their potential for thermoelectric applications. Strong correlation effects have been observed in a number of cage compounds containing Ce. While the thermoelectric performance of some of these is promising, further optimization will be needed to bring these materials to practical use